A pulse combustor typically comprises a combustion chamber, air and fuel inlets and an exhaust duct or resonance tube. A pulse combustor cycle consists of an explosion in the combustion chamber forcing combustion products out the exhaust duct, the consequent drawing of fuel and air into the evacuated combustion chamber and the ignition of the fresh fuel mixture by residual hot gases to complete the cycle. Backflow of exhaust gases out the air inlet is suppressed by mechanical or aerodynamic valves on the air inlet. The unit cycles close to its natural acoustic frequency.
The pulse combustor is an efficient heating device because of the high flow rates or high pressure boost of the exhaust gases. This results in high heat transfer rates in the resonance tube and the ability to use a compact, efficient heat exchanger in removing large quantities of heat.
The well known disadvantages of vibration and noise have thus far prevented the wide spread use of pulse combustors despite their high efficiency and other advantages. Use of exhaust and inlet mufflers has been suggested to reduce noise. The present inventor has also suggested the use of multiple pulse combustor units which are joined to operate out of phase and thereby provide acoustic cancellation of noise. The suggestion appears in a paper entitled "General Survey of Pulse Combustion," in Proceedings of the First International Symposium on Pulsating Combustion, Sept. 20-23, 1971, University of Sheffield S1 3JD, England. Another paper by the inventor entitled "A Review of Pulse-Combustor Technology" presented at a symposium on Pulse Combustor Technology for Heating Applications at Argonne National Laboratory, Nov. 29-30, 1979, also surveys pulse combustors.
Other related information is contained in the U.S. Pat. Nos. 2,515,644 Goddard; 2,525,782 Dunbar; 2,546,966 Bodine; 2,878,790 Paris; 2,911,957 Kumm; 2,998,705 Porter; 3,118,804 Melenric; 3,267,985 Kitchen; 3,323,304 Llobet; 3,365,880 Grebe; 3,498,063 Lockwood; 3,792,581 Handa, and 4,033,120 Kentfield.